Arsenic, a highly poisonous metallic element that is found in rocks, soils and waters, affects more than 100 million people worldwide, according to the World Health Organization (WHO). WHO reports that arsenic poisoning is prevalent in a number of countries around the world, including Bangladesh, India, Argentina and China, including Taiwan. WHO estimates that arsenic in drinking water will cause 200,000 to 270,000 deaths from cancer in Bangladesh alone. In the United States, the Environmental Protection Agency reports that thirteen million people in more than twenty states are affected by arsenic contaminated drinking water. Medical problems linked to arsenic ingestion include skin cancer and bladder cancer, among other illnesses.
Industrial technologies for removal of arsenic from water include: precipitation processes, adsorption processes, ion exchange (IX) processes, membrane filtration, alternative treatment processes such as greensand filtration, and point-of-use devices (POU). There are a number of developing technologies for the removal of heavy metals from drinking water, including: iron oxide coated sand, nanofiltration, iron filings, sulfur-modified iron, granular ferric hydroxide, biological settling processes and plant intake methods. However, these technologies often require multiple treatment stages or combination of various technologies to achieve acceptable water quality, and are difficult and expensive to manufacture and operate. Additionally, there is a big problem with safe and effective waste disposal after the water has been purified using the above technologies.
Accordingly, robust and affordable technologies to handle arsenic and/or heavy metal removal from water, as well as safe disposal of these toxic substances, appear as the best option to resolve increasing health problems associated with arsenic and/or heavy metal contamination.